* .x-sc_prohibit_doubled_word: don't perform this check on
xargs/testsuite/xargs.sysv/iquotes.xo or ChangeLog.
Don't check .po files for doubled English words (because they're
not in English).
* find/tree.c: Modify some text to avoid saying "AND and",
which one of the syntax checks doesn't like.
(opt_expr): Likewise.
(consider_arm_swap): Likewise.
* README: Likewise.
* configure.ac (DEFAULT_ARG_SIZE): Check environment for a default
size override.
* lib/buildcmd.c (bc_use_sensible_arg_max): Use default size from
configure, if requested.
* README (DEFAULT_ARG_SIZE): Mention the ability to tune this at
configure time.
* NEWS: Document the change.
